Fluid pressure device with dual feed and exhaust



Nov. 14, 1967 w, EASTON 3,352,247

FLUID PRESSURE DEVICE WITH DUAL FEED AND EXHAUST Filed Dec. 8, 1965 4 Sheets-Sheet 1 INVEN'IOR. M 6. 14570 Nov. 14, 1967 w. B. EASTON FLUID PRESSURE DEVICE WITH DUAL FEED AND EXHAUST 4 Sheets-Sheet 2 Filed Dec. 8, 1965 MYNE 5.514570 Nov. 14, 1967 w. B. EASTON 3,352,247

I FLUID PRESSURE DEVICE WITH DUAL FEED AND EXHAUST Filed Dec. 8, 1965 4 Sheets-Sheet 5 .9 1017] lj l rig Nov. 14, 1967 w. B. EASTON 3,352,247

FLUID PRESSURE DEVICE WITH DUAL FEED AND EXHAUST Fild Dec. 8, 1965 4 Sheets-Sheet 4 mzQ 4w 10 9 9 1., 2 INVENI'OK.

101 137 W'AYNE BEASTON United States Patent OflFice 3,352,247 Patented Nov. 14, 1967 3,352,247 FLUID PRESSURE DEVICE WITH DUAL FEED AND EXHAUST Wayne B. Easton, South Bend, Ind., asslgnor to Cha1'- Lynn Company, Eden Prairie, Minn., a corporation of Minnesota Filed Dec. 8, 1965, Ser. No. 512,398 13 Claims. (Cl. 103-130) This invention relates to fluid pressure devices such as pumps, motors and meters which utilize a gerotor and more particularly to fluid passage arrangements for feeding fluid to and exhausting fluid from such devices.

Gerotor gear sets are well known in the art and in general comprise a pair of inner and outer gears with the inner externally toothed star gear having at least one less tooth than the outer internally toothed ring gear. The star gear is eccentrically mounted relative to the ring gear and there are various combinations wherein the axes of the gears may be fixed relative to each other or there may be relative orbital movement between the axes of the gears. Of the various possible combinations which involve relative orbital movement between the gears, either gear may (1) be stationary, (2) have orbital and rotational movement, (3) have only orbital movement or (4) have only rotational movement.

It is known that when orbiting type gerotors are used for fluid pressure devices such as pumps, motors and meters, the fluid feeding and exhausting of the gerotor must be performed at the orbiting speed of the orbiting gear.

In one type of such a fluid pressure device a valve is provided which rotates in synchronism with the orbiting of the orbiting gear and fluid passages are provided in the valve which, in general, consists of fluid feeding passage means on one side of the valve and fluid exhausting passage means on the other side of the valve. This valve may be referred to as a high speed valve because it rotates at the orbital speed of the gerotor unit which speed is several times faster than the rotational speed of the gerotor unit.

In a second type of such a fluid pressure device there is provided a fluid feeding and exhausting valve that rotates in synchronism with the rotational movement of the orbiting gear. As the rotational speed factor of a gerotor unit is only a fraction of the orbital speed factor, this valve may be referred to as a slow speed valve. Valve passages are provided in the slow speed valve in accordance with a known principle which causes fluid to be supplied to and exhausted from the gerotor at high speed in synchronism with the orbital speed of the gerotor despite the fact that the rotational speed of the slow speed valve is only a fraction of the orbiting speed of the gerotor unit. The slow speed valve may be referred to as a commutator valve because its fluid feeding and exhausting characteristics in relation to an orbital type gerotor are analogous in some respects to electrical commutation. In this specification and appended claims, therefore, the words commutator and commutation means, applied to the field of hydraulics and pneumatics, the particular type of slow speed valve referred to above and its particular feeding and exhausting characteristics it has in relationship to an orbital type gerotor.

In prior art gerotor type fluid pressure devices the mode of operation of the valve thereof, whether high speed or slow speed, is such that the diflerence in pressure between the feeding and exhausting fluids creates a resultant unbalanced force on one side of the valve axis which accelerates the wear on bearings and valve surfaces and which requires the use of relatively heavy duty thrust bearings.

It is a main object of the present invention to provide gerotor type fluid pressure devices having porting and passage arrangements which cause certain of the pressurized fluids acting on the valve to be balanced. It is a further object of the invention that the porting and passage arrangements so provided also serve to double the number of passages between the valve and the gerotor and thereby increase the fluid flow capacity of the device between the valve and gerotor.

Other objects and advantages will become apparent from the following specification, appended claims and attached drawings.

In the drawings:

FIG. 1 is a longitudinal sectional view of a fluid pressure motor or pump of the slow speed valve type embodying the invention and taken on line 11 of FIG. 3;

FIGS. 2 to 5 are transverse sectional views taken on lines of FIG. 1 which correspond to the figure numbers;

FIG. 6 is a view taken from the right end of the device of FIG. 1;

FIG. 7 is a longitudinal sectional view of a fluid pressure motor or pump of the high speed valve type embodying the invention and taken on line 77 of FIG. 11.

FIG. 8 is a longitudinal sectional view similar to FIG. 7 except that it is a partial view and is taken on line 8-8 of FIG. 12; and

FIGS. 9 and 13 are transverse sectional views taken on lines of FIG. 7 which correspond to the figure numbers.

In the fluid pressure motor or pump illustrated in FIGS. 1 to 6 there is provided a casing or housing made of several sections which are a valve section 2, a fluid passage section 4, a gerotor section 6, a fluid passage section 7 and an end cap 8. Casing sections 2, 4, 6, 7 and 8 are held together in axial alignment by a plurality of circumferentially spaced bolts 9.

Casing section 2 is provided with inlet and outlet ports 14 and 16 which would be reversed for operation of the pump or motor in the opposite direction.

The shape of gerotor casing section 6 is generally cylindrical and annular and has a plurality of internal teeth. An externally toothed star member 18 having at least one fewer teeth than casing section 6, which may be referred to as a ring member 6, has the teeth thereof in meshing engagement with the teeth of ring member 6. Star member 18 partakes of a hypocycloidal movement and travels in an orbit about the axis of ring member 6. The gerotor mechanism may be used as a fluid pressure motor, pump or meter and will be described more fully later on.

Valve casing section 2 has a generally cylindrical shape and has an exially extending bore 20 and a counterbore 22, both of which bores are concentric relative to the axis 24 of ring member 6. Inlet and outlet ports 14 and 16 communicate with the interior of bore 22 as shown in FIG. 1. Rotatably disposed in valve casing section 2 is a combination valve and shaft member which comprises a cylindrically shaped valve 28 which is rotatably supported in bore 22 and a shaft 30 which is rotatably sup- Shaft 30 is an input shaft if the device as a motor. The ax1al length of valve portion 28 is equal to the axial length of counterbore 22 so that the radial surface 32 of valve portion 28 is in sliding engagement with the adjacent radial surface 34 of casing section 4.

With reference to FIG. 4, the gerotor casing section 6, which in effect is the ring member 6, has a plurality of internal teeth 36. Externally toothed star member 18, having at least one fewer teeth 37 than n'ng member 6, is disposed eccentrically in the chamber or space formed and surrounded by ring member 6. Star member 18 is moveable orbitally relative to the ring member 6 with the axis 38 of star member 18 being movable in an orbital path about the axis 24 of ring member 6. During orbital movement of star member 18 the teeth 37 thereof intermesh with the ring member teeth 36 in sealing engagement to form expanding and contracting cells 39 to 44 which are equal in number to the number of teeth 37 of star member 18.

With further reference to FIG. 4, a vertical centerline 45 incidentally represents the line of eccentricity for the star member 18 for that particular position of the star member relative to the ring member 6. The line of eccentricity is defined herein as a line or plane which is perpendicular to and intersects the star and ring axes 138 and 24 for all orbital positions of the star 18. During orbital movement of the star member 18, and assuming the orbital movement is clockwise as viewed in FIG. 4, the cells 42 to 44 on the left side of the line of eccentricity would be expanding and the cells 39 to 41 on the right side would be contracting. If the device is used as a motor, fluid under pressure is directed to the expanding cells and exhausted from the contracting cells. If the device is used as a pump, fluid is sucked into the expanding cells and delivered under pressure from the contracting cells. The valving arrangement which facilitates the pumping or motor action will be described further on herein.

Casing section 4 has a bore 46 which is concentric relative to the axis 24 and is of small enough diameter so that the resulting annular face 48 which abuts gerotor casing section 6, along with casing section 7, form sides for the gerotor chamber so that the expanding and contracting cells 39 to 44 formed betweenthe teeth of the gerotor star and ring members 18 and 6 will be closed for all orbital positions of the star member 18.

Star member 18 has a bore 50 which is concentric relative to the teeth 37 thereof and the bore 50 is provided with a plurality of circumferentially arranged, axially extending teeth or splines 52. A bore 54 of valve 28, which is concentric relative to axis 24 and communicates with the bore 46 and 50 of casing section 4 and star 18, also has a plurality of circumferentially arranged, axially extending teeth or splines 56. A shaft 58, which may be referred to as a dogbone because of its general appearance, extends between and mechanically connects star 18 and valve 28 in driving relation. Heads 60 and 62 at opposite ends of dogbone 58 are frustospherically shaped and are provided with splines which are equal in number to and mesh with splines 52 and 56 of the star and valve members 18 and 28.

In operation a star member 18 having six teeth will make one revolution about its own axis 38 for every six times the star member orbits in the oppositedirection about the axis 24 of the ring member 6. Thus, the right end of the dogbone 58 has both orbital and rotational movement in common with the star member 18 while the left'end of the dogbone has only rotational movement in common with valve 28;

The spline connections between dogbone 58 and valve 28 on the one hand, and between dogbone 58 and star member 18 on the other hand, are forms of universal joints which permit the dogbone to have the motion described above. When the device is utilized as a pump, star member 18 will be gyrated by a turning force applied to shaft 30 which is transmitted to star member 18' through the dogbone 58. When the device is used as a motor, the force created by the rotation of star member 18 about its own axis 38 will be transmitted through dogbone 58 to shaft 30 to cause turning of shaft 30.

Valve 28 and casing sections 2, 4, 6, 7 and 8 are provided with fluid passages through which fluid is conveyed from the port 14 or 16 to the cells of the gerotor on one side of the line of eccentricity 45 and exhausted from cells on the other side of the line of eccentricity to the other of the ports 14 or 16. Port 14 or 16 will be the inlet, and the other the outlet port, depending on the direction of rotation desired for shaft 30. Valve 28, by reason of the dogbone connection between it and star 18, will rotate at the same speed as the star 18 butin the opposite direction from the orbiting direction of the star 18. Valve 28 has two axially spaced annular channels 64 and 66 and which are axially aligned with ports 14 and 16 and in respective fluid communication therewith. Assuming for purposes of illustration that port 14 is the inlet port, valve 28 has a plurality of circumferentially arranged and spaced fluid feeding passageswhich are illustrated herein as a set of six circumferentially arranged, radially extending holes 71 to 76 which intersect and have fluid communication with six axially extending passages 77 which in turn have fluid communication with annular channel 64 and port 14 through a set of radially extending passages 78. Valve 28 also has a plurality of circumferentially arranged and spaced fluid exhausting passages, which are alternately arranged relative to the fluid feeding passages 71 to 76, which are illustrated as a set of six axially extending slots 81 to 86 which intersect and have fluid communication with annular channel 66 which has fluid communication with outlet port 16. In the fluid pressure device illustrated, the passages 71 to 76 and the passages 81 to 86 are equal in number to the number of teeth 37 on the star 18. Fluid feeding passages 71 to 76 and fluid exhausting passages 81 to 86 are in the plane of line 33 and that plane will be referred to herein for convenience as the commutating plane 3-3. The invention does not. require that passage set 71 to 76 and passage set 81 to 86 be in one plane, however, and in other embodiments the passage sets could be indifferent planes.

Casing sections 2 and 4 have a plurality of passages 91 to 97 formed therein which have radially extending portions which open into the casing bore 22 and which form circumferentially arranged and spaced openings in the commutating plane 3-3. Casing passages 91 to 97 have axially extending portions which have openings in the radial face 48 of casing section 4 and have fluid communication with the chamber formed by casing section 6 at points respectively between the ring member teeth 36. Casing passages 91 to 97 may be, within the scope of the invention, one more or one less in number than the set of valve passages 71 to 76 or the set of valve passages 81 to 86. In this embodiment of the invention the casing passages 91 to 97 are one more in number than either of the sets of valve passages and are equal in number to the number of teeth 36 of ring member 6.

Casing sections 2, 4, 6, 7 and 8 have a plurality of pasages 101 to 107 formed therein which have radially ex-.

tending portions in casing section 2 which open into casing bore 22 and which form circumferentially arranged and spaced openings in the commutating plane 33 which are alternately arrangedrelative to the openings of passages 91 to 97 in plane 33. The passages 101' to 107 are equal in number to the passages 91 to 97. Casing passages 101 to 107 have axially extending portions in casing section 2, 4 and 6 with the passage portions in casing section 6 being formed in the bodies of the ring member teeth 36. Casing section 7 has a first set of axially extending, circumferentially arranged and spaced holes 101 to 107 which are axially aligned respectively with casing passages 91 to 97 and which have fluid communication with the chamber formed by casing section 6 at points respectively between the ring member teeth 36. Casing section 7 has a second set of axially extending, circumferentially arranged and spaced holes 101 to 107 which are alternately arranged relative to the first set of holes 101 to 107 in casing section 7 and are axially aligned respectively with the casing passages 101 to 107 in casin g section 6. It will thus be noted that passages 91 to 97 in casing section 4 and one set of the passages 101 to 107 in casing section 7 have fluid communication with the chamber formed by casing section 6 from opposite sides of the gerotor which comprises ring member 6 and star 18.

End cap 8 has a plurality of passages 101 to 107 with each passage having two openings in the surface 110 thereof, on diametrically opposite sides thereof, which is in abutting engagement with casing section 7. The two sets of openings for the passages 101 to 187 in end cap 8 are aligned respectively with the two sets of openings 101 to 107 in casing section 7 so that each of the passages 101 to 187 starts in casing section 2, extends through casing sections 4, 6 and 7, through end cap 8, and again through casing section 7 to a point between two ring member teeth 36. Each of the passages in end cap 8, such as passage 161, extends diametrically across the cap and has two axially extending portions which are aligned with and register with corresponding passages in casing section 7.

Each of the passages 91 to 97 is thus paired with one of the passages 101 to 107 via fluid passages in casing end cap 8 so that each pair of passages which consist of two passages on opposite sides of the casing in commutating plane 3-3, such as passages 91 and 181 (see FIGS. 1 and 3), function to jointly convey fluid to an expanding cell and jointly convey fluid away from a contracting cell.

If desired, the axially extending portions of easing passages 101 to 107 could be made larger in diameter so as to accommodate bolts 9 as well as the flow of fluid therethrough. This modification would permit a smaller diameter for the casing sections 2, 4, 6, 7 and 8.

Upon rotation of valve 28, each of the openings of passages 71 to 77 and 81 to 87, successively registers in fluid communication with the openings of passages 91 to 97 and 101 to 107 in casing section 4. If the fluid pressure device is functioning as a motor, pressurized fluid may be introduced through port 14 from where it would flow into annular channel 64 of valve 28 and through passages 78 and 77 to fluid feeding passages 71 to 76 of valve 28. The flow conditions at the instant when valve 28 and star 18 are in the position shown in FIGS. 3 and 4 are that fluid is flowing respectively from valve passages 71 to 76 into casing passages 105 to 107 and 95 to 97. The fluid in casing passages 95 to 97 is flowing to the left side of the gerotor as viewed in FIG. 1 to cells 42 and 44 (see FIG. 4) which are expanding. The fluid in casing passages 105 to 187 is flowing to the right side of the gerotor as viewed in FIG. 1 via end cap 8 and also enters into expanding cells 42 to 44. The expansion of cells 42 to 44 on the left side of the line of eccentricity 45 (see FIG. 4) causes star 18 to gyrate in a clockwise direction and causes collapsing of the cells 39 to 41 on the right side of the line of eccentricity 45. Fluid from the collapsing cells 39 to 41 flows from the left side of the gerotor as viewed in FIG. 1 through casing passages 92 to 94 to fluid exhausting passages 81 to 83 of valve 28. Fluid from the collapsing cells 39 to 41 flows from the right side of the gerotor as viewed in FIG. 1 via end cap 8 through casing passages 102 to 104 to fluid exhausting passages 84 to 86 of valve 28. The fluid from the fluid exhausting passages 81 to 86 of valve 28 flows to annular channel 66 of valve 28 and out outlet port 16. Considering one cell at a time, it may be noted that fluid from valve feeding passages 72 and 75 flows through casing passages 106 and 96 respectively to expanding cell 43 and that fluid from contracting cell 40 flows through casing passages 93 and 183 to valve exhausting passages 82 and 85 respectively. As long as pressurized fluid is admitted through port 14, however, the pressurized fluid will always be admitted to gerotor cells on the same side of the line of eccentricity 45 and fluid will always be exhausted on the other side of said line.

In the embodiment of the invention illustrated in FIGS. 1 to 6 the circumferential dimensions of valve passages 71 to 76 and 81 to 86 in plane 33 are determined by dividing the circumference of valve 28 into twenty-four equal segments, which is equal to twice the number of valve passages, so that the circumferential dimensions of all the passages and the spaces that separate them are all equal. The circumferential dimensions of each of the casing passages 91 to 97 and 101 to 107 in plane 3-3 is equal to A of the circumference of valve 28.

During orbiting of star 18 about ring member axis 24, the star rotates in the opposite direction about its own axis 38 at a slower speed. The ratio between the orbiting and rotating speeds is dependent upon the ratio between the ring and star member teeth. If that ratio is seven to six as illustrated herein, the rotating speed of the star will be one-sixth of its orbiting speed. By reason of the dogbone connection between star 18 and valve 28, valve 28 rotates at the same speed and in the same direction as star 18. Valve 28 is a commutating type valve in that it rotates at the same speed that star 18 rotates but it functions to supply and exhaust fluid to and from the gerotor at the orbiting frequency of the star.

A main object of the invention is to provide fluid pressure balance for the valve 28. In this connection it may be noted above that when fluid under pressure is admitted to port 14 all of the fluid feeding passages 71 to 76 of valve 28 are supplied with pressurized fluid which occupies all of these passages at all times. In the construction illustrated, pressurized fluid continuously flows outwardly from each pair of diametrically opposite valve passages, such as the pairs 71-74, 72-75 and 7376, to various ones of the casing passages 91 to 97 and 101 to 107 regardless of the angular position of valve 28. As the same is true with respect to the fluid exhausting passages 81 to 86 of valve 28 except that the flow is from the casing passages to the valve passages, valve 28 is balanced at all times relative to the fluid pressure forces acting on it.

The fluid pressure motor or pump illustrated in FIGS. 7 to 13, which is the high speed valve type, has several parts which are identical to corresponding parts of the device shown in FIGS. 1 to 6 and will not be described again. The parts of the device of FIGS. 1 to 6 which are identical to corresponding parts in FIGS. 7 to 13 are the casing sections 4, 6 and 7, end cap 8 and the bolts 9. The parts of the second device which are the same as corresponding parts of the first device have the same reference numerals associated therewith.

A valve casing section 112 is illustrated as being identical to valve casing section 2 of the first embodiment of the invention except for a slight change in the positioning of the passages formed therein. In the second embodiment, casing section 112 has a generally cylindrical shape and has an axially extending bore and a counterbore 122, both of which bores are concentric relative to the axis 124 of ring member 6. Inlet and outlet ports 114 and 116 communicate with the inerior of bore 122 as shown in FIGS. 7 and 8.

Referring further to FIGS. 7 to 13, there is rotatably disposed in valve casing section 112 a combination valve and shaft member which comprises a cylindrically shaped valve 128 which is rotatably supported in counterbore 122 and a shaft 139 which is rotatably supported in bore 120. Shaft 130 is an input shaft if the device is used as a pump and an output shaft if the device is used as a motor. The axial length of valve portion 128 is equal to the axial length of counterbore 122 so that the radial surface 132 of valve portion 128 is in sliding engagement with the adjacent radial surface 34 of casing section 4.

The star 118 of the second device has one fewer teeth 137 than the ring member 6 and differs from the star 18 of the first device only by having a cylindrical bore 150 that is concentric to the axis 140 thereof instead of a splined bore.

Expanding and contracting cells 142 are formed between star 118 and ring 6 and star 118 has the same relationship and the same orbital and rotational movements relative to ring 6 as does star 18 of the first device.

A bore 154 formed in valve 128 is concentric relative to ring axis 124 and has communication with the bore 46 of casing section 4 and bore of star 118. Valve bore 154 is provided with circtunferentially arranged, axially extending teeth or splines 156. A shaft 158 extends between and mechanically connects star 118 and valve 128 in driving relation. Shaft 158 is concentric relative to ring axis 124 and has end portions 160 and 162 which respectively engage star 118 and valve 128. Between end portions 160 and 162 of shaft 158 is a journal portion 163 which has the same diameter as casing bore 46 and rotatably engages bore 46.

End portion 160 of shaft 158 is cylindrically shaped, is eccentrically disposed relative to ring axis 124. and is rotatably disposed in star bore 160. End portion 162 of shaft 158 which engages valve 128 has teeth or splines which are equal in number to and mesh with the teeth or splines 156 of valve 124. With the driving connection between valve 128 and star 118 described, valve 128 will be caused to rotate in synchronism with the orbiting speed of the star 118 instead of the rotating speed of the star as in the device shown in FIGS. 1 to 6.

Valve 128 and casing sections 112, 4,6, 7 and 8 are provided with fluid passages through which fluid is conveyed from the port 114 or 116 to the cells of the gerotor on one side of the line of eccentricity 145 (see FIG. 13) and exhausted from cells on the other side of the line of eccentricity to the other of the ports 114 or 116. Port 114 or 116 will be the inlet, and the other the outlet port, depending on the direction of rotation desired for shaft 130.Valve 128 has two axially spaced annular channels 164 and 166 which are axially aligned with ports 114 and 116 and in respective fluid communication therewith. Assuming for purposes of illustration that port 114 is the inlet port, valve 128 has at least two fluid feeding passages which are illustrated (see FIGS. 7, 8, 11 and 12) herein as are shaped channels 171 and 172 which are disposed on opposite sides of the valve 128 and the line of eccentricity 145 and are respectively disposed in axially spaced, transverse planes 11-11 and 1212. Valve 128 also has at least two fluid exhausting passages which are illustrated herein as are shaped channels 173 and 174 which are disposed on opposite sides of the valve 128 and the line of eccentricity 145 and are respectively disposed in axially spaced, transverse planes 1111 and 1212. Channels 171 and 173 are on opopsite sides of the valve 128 and are circumferentially spaced apartby wall portions 183 and 184 which will be referred to further on. Channels 173 and 174 are likewise on opposite sides of valve 128 and are circumferentially spaced apart by wall portions 185 and 186 which will be referred to further on. Fluid feeding passages 171 and 172 have fluid communication with inlet port 114 through two axially extending passages 177 which have fluid communication with annular channel 164 through radially extending passages 178 and fluid communication with channels 171 and 172 through radially extending passages 179 and 180.

Fluid exhausting passages 173 and 174 have fluid communication with outlet port 116 through two axially extending passages 187 which have fluid communication with annular channel 166 through radially extending passages 188 and fluid communication with channels 173 and 174 through radially extending passages 189 and 190.

Casing section 112 has a plurality of passages 91a to 97a formed therein which have radially extending portions which open into the casing bore 122 and which form circumferentially arranged and spaced openings in the plane 1111 which may be referred to as a distributing plane. Casing passages 91a to 97a have axially extending portions which have openings in the annular face 198 of easing section 112 which register with and have fluid communication respectively with passages 91 to 97 of casing section 4. Casing section 112 also has a plurality of passages 101a to 107a formed therein which have radially extending portions in casing section 112 which open into casing bore 122 and which form circumferentially arranged and spaced openings in the. distributing plane 1212 which are alternately arranged relative to the openings of passages 91a to 97a in plane 11-11. The passages 101a to 107a are equal in number to the passages 91a to 97a. Casing passages 101a to 107a also have axial- 8 ly extending portions which have openings in annular face 198 of casing section 112 which register with and have fluid communication with passages 101 to 187 of casing section 4.

Upon rotation of valve 128, fluid feeding passage 171 and fluid exhausting passage 173 in plane 1111 successively register in fluid communication with casing passages 91a to 97a while fluid feeding passage 173 and fluid exhausting passage 174 in plane 1212 successively register in fluid communication with casing passages 101a to 107a. If the fluid pressure device is functioning as a motor, pressurized fluid may be introduced through port 114 from where it would flow into annular channel 164 of valve 128 and through passages 177 to fluid feeding passages 171 and 172 of valve 28. The flow conditions at the instant when valve 128 and star 118 are in the position shown in FIGS. 11 to 13 are that fluid will be flowing from valve passages 171 and 172 into casing passages a to 97a and a to 107a. The fluid in casing passages 95a to 97a would be flowing to the left side of the gerotor as viewed in FIG. 7 to cells on the left side of the line of eccentricity (see FIG. 13) which are expanding. The fluid in casing passages 105a to 107a would be flowing to the right side of the gerotor as viewed in FIG. 7 via end cap 8 and also enters into the expanding cells on the left side of the line of eccentricity. The expansion of cells 142 on the left side of the line of eccentricity 145 causes star 118 to orbit in a clockwise direction and causes collapsing of the cells 142 on the right side of the line of eccentricity 145. Fluid from the collapsing cells 142 would be flowing from the left side of the gerotor as view in FIG. 7 through casing passages 92a to 94a to fluid exhausting passage 173 of valve 28 in plane 11-11. Fluid from the collapsing cells 142 would also be flowing from the right side of the gerotor as view in FIG. 7 through casing passages 1020: to 104a via end cap 8 to fluid exhausting passage 174 of valve 28 in plane 1212. The fluid fromthe fluid exhausting passages 173 and 174 of valve 28 flows to fluid outlet port 116 through passages 187 (see FIG. 8) and annular channel 166 of valve 28. Considering one cell ata time, it may be noted that fluid from valve feeding passages 171 and 172 would be flowing through casing passages 96a and 106a to expanding cell A and that fluid from contacting cell B would be flowing through casing passages 93a and 103a to valve exhausting passages 173 and 174. As long as pressurized fluid is admitted through port 114, however, the pressurized fluid will always be admitted to gerotor cells on the same side of the line of eccentricity 145 and fluid will always be exhausted on the other side of said line.

In the embodiment of the invention illustrated in FIGS. 7 to 13, channels 171 and 173 of valve 28 (see FIG. 11) are spaced apart by wall portions 183 and 184 a distance equal to the diameter of each of the openings of passages 91a to 97a in plane 11-11. Likewise, channels 172 and 174 of valve 28 (see FIG. 12) are spaced apart by wall portions 185 and 186 a distance equal to the diameter of each of the openings of passages 1010 to 107a in plane 1212.

During orbiting of star 118 about ring member axis 124, valve 128 rotates in the same direction and at the same speed as the orbiting speed of the star by reason of the crank type shaft 158 disposed between star 118 and valve 128. Valve 128 is a distributing type valve in that it rotates at the same speed that star 118 orbits and functions to supply and exhaust fluid to and from the gerotor at the orbiting frequency of the star.

The separation between channels 171 and 173 by wall portion 183 and 184, and between channels 172 and 174 by wall portions 185 and 186, facilitates the change from pressure to exhaust, and from exhaust to pressure, for each of the casing passages 91a to 97a and 101a to 107a during each cycle of operation. With star 118 in the position illustrated and assuming it is orbiting in a clockwise direction, the casing passages 91a and 101a (see FIGS.

11 and 12) have at that instant just finished exhausting fluid from fluid exhausting pasasges 173 and 174 and in the next instant, after valve 128 has rotated a slight distance further in a clockwise direction, will receive fluid from fluid feeding passages 172 and 173. Wall portions 183 to 185 cooperate successively with the casing passages 91a to 97a and 101a to 107a in the manner described so that pressure is always maintained in the gerotor cells on one side of the line of eccentricity 145 and so that fluid is exhausted from the cells on the other side of the line of eccentricity, depending on which of the ports 114 or 116 is the inlet port.

In the second embodiment of the invention, valve 128 is better balanced hydraulically than are valves in prior art gerotor type fluid pressure devices having the high speed type of valve. In this connection it may be noted that when fluid under pressure is admitted to port 114, pressurized fluid is delivered to both sides of valve 128 by reason of it being delivered to fluid feeding passages 171 and 172 which are on opposite sides of the valve. The pressurized fluid continuously flows outwardly from passages 171 and 172 to casing passages 91a to 97a and 101a to 107a regardless of the angular position of valve 128 and the symmetry achieved by having fluid feeding passage 171 to communicate with the set of casing passages 91a to 97a and fluid feeding passage 172 communicate with the set of casing passages 101a to 107a creates a balance of the radially directed fluid pressure forces acting on valve 128. As the same is true with respect to the fluid exhausting passages 173 and 174 of valve 128 except that the flow is from the casing passages to the valve passages, valve 128 is balanced at all times with respect to the radially directed fluid pressure forces acting on it.

While two embodiments of the invention are described here, it will be understood that they are capable of modification, and that such modification, including a reversal of parts, may be made without departure from the spirit and scope of the invention as defined in the claims.

What I claim is:

1. A rotary fluid pressure device comprising a casing, fluid inlet and outlet means, a ring member defining a chamber and having a plurality of circumferentially spaced internal teeth, a cooperating externally toothed star member having fewer teeth than said ring member disposed eccentrically relative to the axis of said ring member, one of said members having rotational movement about its own axis and one of said members having orbital movement about the axis of the other of said members with the teeth of said members intermeshing in sealing engagement to form expanding cells on one Side of the line of eccentricity and contracting cells on the other side of said line during relative movement between said members, a valve rotatably disposed in said casing, drive means connecting said valve to one of said members for rotation of said valve in synchronism with one of said movements of one of said members, said valve having fluid feeding passages in fluid communication with said fluid inlet means and fluid exhausting passages in fluid communication with said fluid outlet means, said casing having two sets of passages communicating with said ring chamber at points between said ring member teeth, said passages having circumferentially arranged openings for fluid communication with said fluid feeding and exhausting passages of said valve to effect communication between said inlet means and said expanding cells on one side of said line of eccentricity and between said outlet means and said contracting cells on the other side of said line of eccentricity during rotation of said valve, said openings of said first set of passages being alternately arranged relative to said openings of said second set of passages with each of said openings in one of said sets of passages forming a pair with and being disposed on diametrically opposite sides of said casing from one of said passage openings of the other of said sets of passages, the passages of each of said pair of openings having communication with said chamber between the same pair of adjacent ring member teeth.

2. A fluid pressure device according to claim 1 wherein said fluid feeding and exhausting passages of said valve and said openings of said casing passages are in a single plane which extends perpendicularly relative to the axis of said ring member.

3. A fluid pressure device according to claim 1 wherein said first set of casing passages has fluid communication with said chamber at points on one side of said ring member and said second set of casing passages has fluid communication with said chamber at points on the other side of said ring member.

4. A fluid pressure device according to claim 1 wherein said ring member is stationary relative to said casing and said star member has rotatable movement about its own axis and orbital movement about the axis of said ring member.

5. A fluid pressure device according to claim 4 wherein said drive means effects rotation of said valve in synchronism with said rotational movement of said star member.

6. A fluid pressure device according to claim 5 wherein said fluid feeding and exhausting passages of said valve comprises a series of circumferentially arranged fluid feeding passages and a series of circumferentially arranged fluid exhausting passages arranged alternately relative to said fluid feeding passages.

7. A fluid pressure device according to claim 6 wherein said valve feeding and exhausting passages are two less in number than said casing passages.

8. A fluid pressure device according to claim 4 wherein said drive means effects rotation of said valve in synchronism With said orbital movement of said star member.

9. A fluid pressure device according to claim 8 wherein said openings of said first set of said casing passages are in a first plane and said openings of said second set of said casing passages are in a second plane, said fluid feeding passages of said valve comprising at least one passage in said first plane on one side of said valve and at least one passage in said second plane on the other side of said valve, said fluid exhausting passages of said valve comprising at least one passage in said first plane on said other side of said valve and at least one passage in said second plane on said one side of said valve.

10. A fluid pressure device according to claim 9 wherein said fluid feeding and exhausting passages of said valve in said first plane are circumferentially spaced apart distances equal to the circumferential width of one of said passage openings in said first plane.

11. A fluid pressure device according to claim 4 wherein said valve is on one side of said ring member and said second set of said casing passages is formed partially in said ring member.

12. A fluid pressure device according to claim 11 wherein a portion of said casing is on the opposite side of said ring member from said valve, said second set of said casing passages being formed partially in said portion of said casing.

13. A fluid pressure device according to claim 12 wherein said portion of said casing is an end cover.

References Cited UNITED STATES PATENTS 3,106,163 10/1963 Mosbacher 103-130 3,215,043 11/1965 Huber 9156 3,233,524 2/1966 Charlson 9156 3,270,683 9/1966 McDermott 103-130 3,272,142 9/1966 Easton 103-130 3,288,078 11/1966 Monroe et al 103-130 3,289,542 12/1966 Fikse 91-56 3,289,602 12/1966 Hudgens 103-130.

LAURENCE V. EFNER, Primary Examiner. WILBUR J. GOODLIN, Examiner. 

1. A ROTARY FLUID PRESSURE DEVICE COMPRIISNG A CASING, FLUID INLET AND OUTLET MEANS, A RING MEMBER DEFINING A CHAMBER AND HAVING A PLURALITY OF CIRCUMFERENTIALLY SPACED INTERNAL TEETH, A COOPERATING EXTERNALLY TOOTHED STAR MEMBER HAVING FEWER TEETH THAN SAID RING MEMBER DISPOSED ECCENTRICALLY RELATIVE TO THE AXIS OF SAID RING MEMBER, ONE OF SAID MEMBERS HAVING ROTATIONAL MOVEMENT ABOUT ITS OWN AXIS AND ONE OF SAID MEMBERS HAVING ORBITAL MOVEMENT ABOUT THE AXIS OF THE OTHER OF SAID MEMBERS WITH THE TEETH OF SAID MEMBERS INTERMESHING IN SEALING ENGAGEMENT TO FORM EXPANDING CELLS ON ONE SIDE OF THE LINE OF ECCENTRICITY AND CONTRACTING CELLS ON THE OTHER SIDE OF SAID LINE DURING RELATIVE MOVEMENT BETWEEN SAID MEMBERS, A VALVE ROTATABLY DISPOSED IN SAID CASING, DRIVE MEANS CONNECTING SAID VALVE TO ONE OF SAID MEMBERS FOR ROTATION OF SAID VALVE IN SYNCHRONISM WITH ONE OF SAID MOVEMENTS OF ONE OF SAID MEMBERS, SAID VALVE HAVING FLUID FEEDING PASSAGES IN FLUID COMMUNICATION WITH SAID FLUID INLET MEANS AND FLUID EXHAUSTING PASSAGES IN FLUID COMMUNICATION WITH SAID FLUID OUTLET MEANS, SAID CASING HAVING TWO SETS OF PASSAGES COMMUNICATING WITH SAID RING CHAMBER AT POINTS BETWEEN SAID RING MEMBER TEETH, SAID PASSAGES HAVING CIRCUMFERENTIALLY ARRANGED OPENINGS FOR FLUID COMMUNICATION WITH SAID FLUID FEEDING AND EXHAUSTING PASSAGES OF SAID VALVE TO EFFECT COMMUNICATION BETWEEN SAID INLET MEANS AND SAID EXPANDING CELLS ON ONE SIDE OF SAID LINE OF ECCENTRICITY AND BETWEEN SAIJD OUTLET MEANS AND SAID CONTRACTING CELLS ON THE OTHER SIDE OF SAID LINE OF ECCENTRICITY DURING ROTATION OF SAID VALVE, SAID OPENINGS OF SAID FIRST SET OF PASSAGES BEING ALTERNATELY ARRANGED RELATIVE TO SAID OPENINGS OF SAID SECOND SET OF PASSAGES WITH EACH OF SAID OPENINGS IN ONE OF SAID SETS OF PASSAGES FORMING A PAIR WITH AND BEING DISPOSED ON DIAMETRICALLY OPPOSITE SIDES OF SAID CASING FROM ONE OF SAID PASSAGE OPENINGS OF THE OTHER OF SAID SETS OF PASSAGES, THE PASSAGES OF EACH OF SAID PAIR OF OPENINGS HAVING COMMUNICATION WITH SAID CHAMBER BETWEEN THE SAME PAIR OF ADJACENT RING MEMBER TEETH. 